MIPS: lantiq: xway: sysctrl: fix the GPHY clock alias names

The dt-bindings for the GSWIP describe that the node should be named
"switch". Use the same name in sysctrl.c so the GSWIP driver can
actually find the "gphy0" and "gphy1" clocks.

Fixes: 14fceff4

 ("net: dsa: Add Lantiq / Intel DSA driver for vrx200")
Cc: stable@vger.kernel.org
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>